• ISSN 1008-505X
  • CN 11-3996/S
魏存, 吕豪豪, 汪玉瑛, 刘玉学, 何莉莉, 杨学云, 杨生茂. 铁改性稻壳生物炭对铵态氮的吸附效果研究[J]. 植物营养与肥料学报, 2021, 27(4): 595-609. DOI: 10.11674/zwyf.20440
引用本文: 魏存, 吕豪豪, 汪玉瑛, 刘玉学, 何莉莉, 杨学云, 杨生茂. 铁改性稻壳生物炭对铵态氮的吸附效果研究[J]. 植物营养与肥料学报, 2021, 27(4): 595-609. DOI: 10.11674/zwyf.20440
WEI Cun, LÜ Hao-hao, WANG Yu-ying, LIU Yu-xue, HE Li-li, YANG Xue-yun, YANG Sheng-mao. Adsorption effectiveness of ammonium nitrogen by iron-modified rice husk biochars[J]. Journal of Plant Nutrition and Fertilizers, 2021, 27(4): 595-609. DOI: 10.11674/zwyf.20440
Citation: WEI Cun, LÜ Hao-hao, WANG Yu-ying, LIU Yu-xue, HE Li-li, YANG Xue-yun, YANG Sheng-mao. Adsorption effectiveness of ammonium nitrogen by iron-modified rice husk biochars[J]. Journal of Plant Nutrition and Fertilizers, 2021, 27(4): 595-609. DOI: 10.11674/zwyf.20440

铁改性稻壳生物炭对铵态氮的吸附效果研究

Adsorption effectiveness of ammonium nitrogen by iron-modified rice husk biochars

  • 摘要:
    目的 研究稻壳生物炭和3种铁改性稻壳生物炭对铵态氮的吸附特性,为其作为添加剂进行炭基肥料的开发提供参考。
    方法 以稻壳为原料,在500℃无氧条件下热解制备稻壳生物炭(RBC),并采用3种工艺制备铁改性稻壳生物炭 (FDRBC、FWRBC和FWBC)。利用比表面积测定仪 (BET) 和扫描电镜 (SEM)、X射线衍射 (XRD)、傅立叶红外光谱 (FT-IR) 等技术对稻壳炭和3种铁改性稻壳炭进行物理性质表征。以稻壳生物炭和3种铁改性稻壳生物炭为材料进行铵态氮吸附试验,采用Langmuir和Freundlich方程对稻壳炭和3种铁改性稻壳炭的等温吸附数据进行拟合;并分别用准一级动力学模型和准二级动力学模型对吸附数据进行拟合。
    结果 1) 经过铁改性,稻壳炭比表面积降低了2.4%~63.7%,孔径平均提高了2.8%~319.2%,pH均降低到5左右;2) FWBC和FWRBC在pH为6时,对NH4+-N的吸附量最大,FDRBC和RBC在pH为7时,对NH4+-N的吸附量最大;3) Langmuir吸附等温方程能够很好地拟合稻壳炭和3种铁改性稻壳炭对铵态氮的吸附数据,RBC、FDRBC、FWRBC和FWBC对铵态氮的最大吸附量分别为2.22、8.82、4.67和3.67 mg/g;4) 稻壳炭和3种铁改性稻壳炭对铵态氮的吸附行为符合准二级动力学方程。
    结论 供试稻壳炭和3种铁改性稻壳炭对铵态氮的吸附主要为单分子层吸附,以化学吸附方式为主。铁改性处理提高了稻壳炭的孔径,降低了pH。对铵态氮的吸附能力以FDRBC最优,用其制备新型肥料可提高肥料的保肥供肥能力。

     

    Abstract:
    Objectives The research studied the adsorption characteristics of rice husk biochar and three iron-modified rice husk biochar to ammonium nitrogen. The aim was to provide a basis for using them as carbon additives to manufacture new fertilizers.
    Methods Biochars (RBC, and FDRBC, FWRBC, FWBC) were produced from rice husk without and with FeCl3 through pyrolysis under an oxygen-limited condition at 500℃. The physico-chemical properties of biochar were detected by a specific surface area analyzer (BET), scanning electron microscopy (SEM), X-ray diffractometer (XRD), and Fourier transforms infrared spectroscopy (FT-IR). A chamber adsorption test was carried out using the rice husk biochar and three iron-modified rice husk biochars. Langmuir and Freundlich’s equations were used to fit the isotherm adsorption data of rice husk charcoal and three kinds of iron-modified rice husk charcoal. The quasi-first-order kinetic model and quasi-second-order kinetic model were used to fit the adsorption data, respectively.
    Results 1) The iron-modified rice husk charcoal’s specific surface area was reduced by 2.4%–63.7%, the average pore diameter increased by 2.8%–319.2%, and the pH reduced to about 5. 2) The adsorption ability of NH4+-N by FWRBC and FWBC was the best under the experimental condition with a pH of 6, while FDRBC and RBC had the best adsorption effect on NH4+-N when the pH was 7. Moreover, the Langmuir equation could better simulate the process of isothermal adsorption of NH4+-N by the 4 kinds of biochar, indicating that the adsorption of NH4+-N by the biochars was mainly due to monomolecular adsorption. 3) The maximum adsorption capacity of RBC, FDRBC, FWRBC and FWBC for ammonium nitrogen were 2.22, 8.82, 4.67, and 3.67 mg/g, respectively. 4) The pseudo-second-order kinetics model better defined the kinetics of the 4 kinds of biochar adsorption of ammonium nitrogen.
    Conclusions The adsorption of rice husk charcoal and the three iron-modified rice husk charcoals on ammonium nitrogen is mainly monomolecular layer adsorption, a subset of chemical adsorption. Iron-modification process enhances aperture and pH of rice husk biochar to a different extent. FDRBC shows the best adsorption capacity of ammonium nitrogen, so it is most prospective in increasing fertilizer’s retention ability as an additive.

     

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